scholarly journals Rapid lipolytic oscillations in ex vivo adipose tissue explants revealed through microfluidic droplet sampling at high temporal resolution

Lab on a Chip ◽  
2020 ◽  
Vol 20 (8) ◽  
pp. 1503-1512 ◽  
Author(s):  
Juan Hu ◽  
Xiangpeng Li ◽  
Robert L. Judd ◽  
Christopher J. Easley

High temporal resolution sampling and quantitative detection of glycerol secretion dynamics from adipose tissue using our automated, droplet-based microfluidic system.

2019 ◽  
Author(s):  
Juan Hu ◽  
xiangpeng li ◽  
Robert L. Judd ◽  
Christopher Easley

Our understanding of adipose tissue biology has steadily evolved. While structural and energy storage functionalities have been in the forefront, a key endocrine role for adipocytes was revealed only over the last few decades. In contrast to the wealth of information on dynamic function of other endocrine tissues, few studies have focused on dynamic adipose tissue function or on tool development toward that end. Here, we apply our unique droplet-based microfluidic devices to culture, perfuse, and sample secretions from primary murine epididymal white adipose tissue (eWAT), and from predifferentiated clusters of 3T3-L1 adipocytes. Through automated control, oil-segmented aqueous droplets (~2.6 nL) were sampled from tissue or cells at 3.5-second temporal resolution, with integrated enzyme assays enabling real-time quantification of glycerol (down to 1.9 fmol droplet<sup>-1</sup>). This high resolution revealed previously unreported oscillations in secreted glycerol at frequencies of 0.2 to 2.0 min<sup>-1</sup> (~30-300 s periods) present in the primary tissue but not in clustered cells. Low-level bursts (~50 fmol) released in basal conditions were contrasted with larger bursts (~300 fmol) during stimulation. Further, both fold changes and burst magnitudes were decreased in eWAT of aged and obese mice. These results, combined with immunostaining and photobleaching analyses, suggest that gap-junctional coupling or nerve cell innervation within the intact ex-vivo tissue explants play important roles in this apparent tissue-level, lipolytic synchronization. High-resolution, quantitative sampling by droplet microfluidics thus permitted unique biological information to be observed, giving an analytical framework poised for future studies of dynamic oscillatory function of adipose and other tissues.


2019 ◽  
Author(s):  
Juan Hu ◽  
xiangpeng li ◽  
Robert L. Judd ◽  
Christopher Easley

Our understanding of adipose tissue biology has steadily evolved. While structural and energy storage functionalities have been in the forefront, a key endocrine role for adipocytes was revealed only over the last few decades. In contrast to the wealth of information on dynamic function of other endocrine tissues, few studies have focused on dynamic adipose tissue function or on tool development toward that end. Here, we apply our unique droplet-based microfluidic devices to culture, perfuse, and sample secretions from primary murine epididymal white adipose tissue (eWAT), and from predifferentiated clusters of 3T3-L1 adipocytes. Through automated control, oil-segmented aqueous droplets (~2.6 nL) were sampled from tissue or cells at 3.5-second temporal resolution, with integrated enzyme assays enabling real-time quantification of glycerol (down to 1.9 fmol droplet<sup>-1</sup>). This high resolution revealed previously unreported oscillations in secreted glycerol at frequencies of 0.2 to 2.0 min<sup>-1</sup> (~30-300 s periods) present in the primary tissue but not in clustered cells. Low-level bursts (~50 fmol) released in basal conditions were contrasted with larger bursts (~300 fmol) during stimulation. Further, both fold changes and burst magnitudes were decreased in eWAT of aged and obese mice. These results, combined with immunostaining and photobleaching analyses, suggest that gap-junctional coupling or nerve cell innervation within the intact ex-vivo tissue explants play important roles in this apparent tissue-level, lipolytic synchronization. High-resolution, quantitative sampling by droplet microfluidics thus permitted unique biological information to be observed, giving an analytical framework poised for future studies of dynamic oscillatory function of adipose and other tissues.


2015 ◽  
Vol 87 (13) ◽  
pp. 6535-6543 ◽  
Author(s):  
Alessandro Zambon ◽  
Alice Zoso ◽  
Onelia Gagliano ◽  
Enrico Magrofuoco ◽  
Gian Paolo Fadini ◽  
...  

2013 ◽  
Vol 219 (2) ◽  
pp. 101-108 ◽  
Author(s):  
Bee K Tan ◽  
Jing Chen ◽  
Raghu Adya ◽  
Manjunath Ramanjaneya ◽  
Vanlata Patel ◽  
...  

Adipolin is a novel adipokine with anti-inflammatory and glucose-lowering properties. Lower levels of adipolin are found in obese and diabetic mice. Polycystic ovary syndrome (PCOS) is a pro-inflammatory state associated with obesity and diabetes. To date, there are no human studies on adipolin. Therefore, we measured serum (ELISA) and adipose tissue adipolin mRNA expression (RT-PCR) and protein concentrations (western blotting) in PCOS and control subjects. We also investigated the ex vivo effect of glucose and metformin on adipolin protein production in human subcutaneous adipose tissue explants. We report novel data that serum and subcutaneous adipose tissue adipolin mRNA expression and protein concentrations were significantly lower in women with PCOS compared with control subjects. Furthermore, Spearman's rank analysis showed that serum adipolin concentrations were significantly negatively correlated with BMI, waist-to-hip ratio, and glucose (P<0.05). However, when subjected to multiple regression analysis, none of these variables were predictive of serum adipolin concentrations (P>0.05). Also, subcutaneous adipose tissue adipolin mRNA expression and protein concentrations were only significantly negatively correlated with glucose (P<0.05). No significant correlations were found with omental adipose tissue adipolin mRNA expression and protein concentrations (P>0.05). Moreover, glucose profoundly reduced and metformin significantly increased adipolin protein production in human adipose tissue explants respectively. Importantly, metformin's effects appear to be via the AMP-activated protein kinase signaling pathway.


2014 ◽  
Vol 221 (1) ◽  
pp. 111-119 ◽  
Author(s):  
Bee K Tan ◽  
Krzysztof C Lewandowski ◽  
Joseph Paul O'Hare ◽  
Harpal S Randeva

There has been intense interest in the adipokines of the C1q complement/TNF-related protein (CTRP) superfamily. Adipolin (CTRP12) has been described as a novel adipokine, abundantly expressed in adipose tissue with insulin-sensitising and anti-inflammatory effects. We wanted to investigate the effects of acute and chronic hyperinsulinaemia on circulating adipolin concentrations (ELISA) via a prolonged insulin–glucose infusion in humans. We also examined the effects of insulin and the insulin sensitiser, rosiglitazone, on adipolin concentrations (western blotting) in human adipose tissue explants. We found that hyperinsulinaemic induction in healthy lean human subjects significantly increased circulating levels of adipolin (P<0.05 and P<0.01). Furthermore, in subcutaneous adipose tissue explants, insulin significantly increased adipolin protein expression and secretion (P<0.05 and P<0.01). This effect was attenuated by the phosphatidylinositol 3-kinase inhibitor, LY294002 (P<0.05). Moreover, the insulin-sensitising peroxisome proliferator-activated receptor γ (PPARγ) agonist, rosiglitazone, significantly increased adipolin protein expression and secretion in subcutaneous adipose tissue explants (P<0.05 and P<0.01). This effect was inhibited by the PPARγ antagonist, GW9662 (P<0.05). Our data provide novel insights into adipolin physiology in human subjects.


BIO-PROTOCOL ◽  
2018 ◽  
Vol 8 (3) ◽  
Author(s):  
Pauline Decaunes ◽  
Anne Bouloumié ◽  
Mikael Ryden ◽  
Jean Galitzky

2013 ◽  
Vol 51 (08) ◽  
Author(s):  
V Zevallos ◽  
P Olinga ◽  
Y Junker ◽  
PB Tung ◽  
N Volz ◽  
...  

2010 ◽  
Vol 6 (2) ◽  
pp. 43 ◽  
Author(s):  
Andreas H Mahnken ◽  

Over the last decade, cardiac computed tomography (CT) technology has experienced revolutionary changes and gained broad clinical acceptance in the work-up of patients suffering from coronary artery disease (CAD). Since cardiac multidetector-row CT (MDCT) was introduced in 1998, acquisition time, number of detector rows and spatial and temporal resolution have improved tremendously. Current developments in cardiac CT are focusing on low-dose cardiac scanning at ultra-high temporal resolution. Technically, there are two major approaches to achieving these goals: rapid data acquisition using dual-source CT scanners with high temporal resolution or volumetric data acquisition with 256/320-slice CT scanners. While each approach has specific advantages and disadvantages, both technologies foster the extension of cardiac MDCT beyond morphological imaging towards the functional assessment of CAD. This article examines current trends in the development of cardiac MDCT.


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